Nonetheless, if you leave in the -2 INT, I think adding something along those lines would be just fine (particularly when coupled with "favored class: any," which is a good ability).
I hadn't thought about the half-orc from that perspective. Without "favored class: any," the only thing differentiating them from full orcs is their attributes and lack of light sensitivity, which really just makes them less orc-y, not different. Interesting.
I do think the favored class versatility loses a bit of oomph when INT and CHA are penalized -- you still won't see many half-orc sorcerers, wizards or bards (or much multiclassing with those classes), and to a lesser extent clerics, rogues and paladins will all feel those stat hits as well. That's one reason I think having barbarian as a favored class makes sense.